Tetrakis(hydroxymethyl)glycoluril in N-methylenation reactions with arylamines

This work shows for the first time the use of tetrakis(hydroxymethyl)glycoluril in the melt N-methylenation reactions of arylamines

Мочевина құрамындағы биологиялық белсенді қосылыстарды анықтауға арналған 1D және 2D NMR спектроскопиясы

Urea (carbamide) is the main end product of amino acids' metabolism in mammals. Extensive research in the field of urea chemistry has contributed to the creation of many biologically active and other compounds based on the carbamide fragment NH–CO–NH. The substituting groups of urea directly affect its properties and characteristics which are reflected in the NMR spectral data and this circumstance can be the basis for the identification of urea derivatives. In this work, chemical shifts in the NMR spectra of urea and its acyclic structure, barbituric series, imidazolidinone series and bicyclic structure derivatives were studied and identified. A system analysis was carried out to determine the effect of the type of substituents on the positions of signals of the NH-CO-NH fragment in the NMR spectra. The possibility of 2D NMR spectroscopy using to simplify the identification procedure for complex mixtures was shown in the paper. The combined use of 1D and 2D NMR spectroscopy is convenient and informative to establish the structure of biologically active compounds. These methods make it possible to determine the presence and type of impurities, as well as to establish the destruction processes leading to the corresponding impurities

Efficient synthesis of tetraacetylglycoluril in the presence of phosphorus-containing catalysts

The effect of phosphorus-containing catalysts, namely phosphorous acid, phosphoric acid, diethyl hydrogen phosphite, and 1-hydroxyethane-1,1-diyldiphosphonic acid (HEDP), in the synthesis of tetraacetylglycoluril by acylation of glycoluril with acetic anhydride at 140°C has been studied. The use of 4 equiv of phosphorous or phosphoric acid with respect to glycoluril has been found to be the most appropriate for achieving the maximum yield (95–98%), and specific effect of HEDP leads to N-acetylation–deacetylation of substrates. The positive effect of phosphorus acids on the formation of tetraacetylglycoluril may be related to not only their catalytic action but also the ability to solubilize the substrate

Urea salts with 1-hydroxyethylidene diphosphonic acid

The reaction of urea with 1-hydroxyethylidene diphosphonic acid in the ratios of 1 : 1, 1 : 2, 1 : 3 wasfirst studied. As a result of the reactions, the corresponding 1 : 2 or 2 : 1 salts were formed, which can exhibitbiological activity. The synthesized compounds were characterized by atomic emission spectroscopy, IR and NMR spectroscopy. According to atomic emission analysis, an increase in the amount of urea from 3 moles or more per 1 mole of 1-hydroxyethylidene diphosphonic acid does not cause an increase in the urea content in the final products. According to NMR spectroscopy data, compounds in the formation of which phosphoryl groups of 1-hydroxyethylidene diphosphonic acid are involved are in dynamic equilibrium salt–free acid

Methods of synthesizing glycoluril-based macrocyclic compounds as precursors for polymeric compounds

This review study considers the classification of data on synthesis methods and practically valuable features of glycoluril-based macrocyclic nitrogen-containing compounds as precursors for polymeric compounds. General data about glycoluril and tetra-N-hydroxymethylglycoluril as parental bases for various macrocyclic compounds were considered. Generalized experimental facts about methods for glycoluril direct N-functionalization and its N-hydroxymethyl derivative reactions in macrocycles and polymeric compound synthesis are given

A study of products of tetrakis(hydroxymethyl)glycoluril dehydroxymethylation in aqueous solutions

It was found that tetrakis(hydroxymethyl)glycoluril is unstable in aqueous solutions and undergoes stepwise dehydroxymethylation. The products of this process were identified by HPLC, 1D and 2D NMR spectroscopy. The main product of hydrolytic degradation at room temperature is tris(hydroxymethyl)glycoluril, which may be conditioned by the thermo dynamic characteristics of the reaction. Further dehydroxymethylation to give di- and monohydroxymethyl glycoluril derivatives occurs under more severe conditions